1. Field of the Invention
In recent years, numerous fuel detergents or "deposit control" additives have been developed. These materials when added to hydrocarbon fuels employed in internal combustion engines effectively reduce deposit formation which ordinarily occurs in carburetor ports, throttle bodies, ventures, intake ports and intake valves. The reduction of these deposit levels has resulted in increased engine efficiency and a reduction in the level of hydrocarbon and carbon monoxide emissions.
Furthermore, as engines age, they suffer from a need for a higher octane base gasoline. It is desirable to produce an additive for gasoline which is not only an effective deposit control additive but also has a low ORI (octane requirement increase) property.
Due to the synthetic procedures employed in the manufacture of many of these deposit control additives, such additives often contain small amounts of residual chlorine. In the past, the amount of residual chlorine contained in these additives was usually considered insignificant in comparison to other sources of chlorine typically present in leaded fuels. However, with the advent of non-leaded gasolines, it has become possible to remove many of these other chlorine sources found in fuels. The removal of chlorine from fuels is particularly advantageous, since the combustion process may convert the chlorine into environmentally undesirable emission products.
It is, therefore, highly desirable to provide fuel compositions which contain deposit control additives which effectively control deposits in intake systems (carburetor, valves, etc.) of engines operated with fuels containing them, but do not contribute to chlorine-containing emissions, and, most preferably have a low ORI effect.
2. Description of the Prior Art
U.S. Patent Nos. 3,438,757 and 3,574,576 to Honnen et al. disclose high molecular weight branched-chain aliphatic hydrocarbon N-substituted amines and alkylene polyamines which are useful as detergents and dispersants in hydrocarbonaceous liquid fuels for internal combustion engines. These hydrocarbyl amines and polyamines have molecular weights in the range of about 425 to 10,000, and more usually in the range of about 450 to 5000. Such high molecular weight hydrocarbyl polyamines are also taught to be useful as lubricating oil additives in U.S. Pat. No. 3,565,804 to Honnen et al. U.S. Pat. Nos. 3,898,056 and 3,960,515 to Honnen et al. disclose a mixture of high and low molecular weight hydrocarbyl amines used as detergents and dispersants at low concentrations in fuels. The high molecular weight hydrocarbyl amine contains at least one hydrocarbyl group having a molecular weight from about 1900 to 5000 and the low molecular weight hydrocarbyl amine contains at least one hydrocarbyl group having a molecular weight from about 300 to 600. The weight ratio of low molecular weight amine to high molecular weight amine in the mixture is maintained between about 0.5:1 and 5:1.
U.S. Pat. Nos. 4,123,232 and 4,108,613 to Frost disclose pour point depressants for hydrocarbonaceous fuels which are the reaction products of an epoxidized alpha olefin containing from 14 to 30 carbon atoms and a nitrogen-containing compound selected from an amine, a polyamine and a hydroxyalkyl amine.
U.S. Pat. No. 3,794,586 to Kimura et al. discloses lubricating oil compositions containing a detergent and anti-oxidant additive which is a hydroxyalkyl-substituted polyamine prepared by reacting a polyolefin epoxide derived from branched-chain olefins having an average molecular weight of 140 to 3000 with a polyamine selected from alkylene diamines, cycloalkylene diamines, aralkylene diamines, polyalkylene polyamines and aromatic diamines, at a temperature of 15.degree. C. to 180.degree. C.
U.S. Pat. No. 3,380,909 to Lee describes the reaction: ##STR1##
This polyaminourea is reacted with an alkylsuccinimide to make an anti-foulant additive.
The same or similar chemistry is shown in U.S. Pat. Nos. 3,491,025 and 3,556,995 also to Lee and the products are taught as useful as detergents-dispersants in lube oils.
U.S. Pat. No. 3,965,084 to Sidney Schiff entitled "Ashless Dispersant Products and Process" relates to improved additives for lubricants and motor fuels which are prepared by reacting a petroleum sulfonic acid with an adduct formed from an amine and either urea or thiourea (see Col. 1, lines 7 et seq.). A wide variety of amines can be used to form the adduct (see Col. 5, lines 14 to 36), but there is no hydroxyl group on Schiff's adduct. The preferred mole ratio of amine to urea or thiourea is 1.5:1 to 2.25:1 (see Col. 5, lines 38-41). Runs 2 and 3, summarized in Table 1 in Col. 7, show the reaction of tetraethylene pentamine (TEPA) (which is outside the definition of useful amines for the subject invention) with urea and footnote "a" of Table 1 shows that Schiff expected the product to be a dimer. There is no teaching in Schiff that a cyclic urea would be formed. One with ordinary skill in the art would expect (from the teachings of Schiff in Table 1 and in the preferred ratios of amine to urea) the formation of a dimer-like product.